This invention relates to a method and control for an HVAC system wherein there are multiple zones, each having a damper. The method and control enable a technician to determine the operating condition of the damper from a remote location.
In a typical ducted heating, ventilating and air conditioning (HVAC) system, a blower at an indoor air handler circulates treated air to various parts of the home through a system of ducts. In a zoned HVAC system, the ducts are divided into several zones, with one zone being associated with each part of the building that is desired to be controlled for comfort independently of the other areas. A set of dampers is installed into the duct segments, with at least one damper being associated with each zone.
Dampers can open or closed to direct more or less air to a particular zone as needed to satisfy a desired comfort level for that zone. In a more advanced system, dampers cannot only be fully open or fully closed, but they can be modulated to a number of intermediate positions to achieve a more precise level of comfort control.
Typically, a zoned HVAC system has an electronic control that sends signals to each damper to cause it to open or close. In a typical HVAC system, such as found in most residential systems, the dampers operate “open loop” or without any feedback to the electronic control regarding a current position. In addition, if there is a fault at a damper, feedback is not provided to the electronic control. Thus, the electronic controls do not have knowledge of the fault. Thus, a control cannot easily determine when the system is not operating properly.
Damper faults can be due to an installation error such as a mis-wiring, a fault in the damper motor, a mechanical blockage that prevents damper movement, etc. During installation or service of the zoned system, it is difficult and time-consuming for a technician to pinpoint the nature of any fault and the zone that is affected.